The difference between ABS and ASA

If you know anything about 3D printing, chances are you’re familiar with ABS filament. It is, after all, the most popular material used by FDM experts. 

And for good reason; ABS is a sturdy plastic with higher melting points than PLA, as well as a long lifespan. This makes it suitable for making replacement parts for cars and machines, even.

ABS, however, is not perfect. It has flaws.

First and foremost, it can be more difficult to print with than PLA, depending on which brand of ABS you have purchased. It also wears under rough weather conditions and yellows under the UV rays of the sun. So if you were wondering why your once-white birdhouse is now tinted yellow, there’s your answer.

 ASA Weather Station

A low-cost weather station printed with our white ASA by Martin 

With this in mind, a new (and I use the term lightly, since something created in the 1970’s can hardly be called “new”) material called ASA filament is now being produced at a level that allows domestic users of low-cost 3D printers to employ it in their machines.

But what separates ASA, or Acrylonitrile Styrene Acrylate for the more technical of you, from ABS? Well, ASA has phenomenal strength and is exceptionally weather and chemical resistant, meaning it will withstand outdoor weather conditions of all sorts with unmatched durability.

Another benefit of ASA plastic is its ability to retain both shape and colour over time. While many filaments will gradually yellow over time, ASA has the lowest levels of yellowing for such a stable, resistant-to-wear printing material.

In addition, ASA has unparalleled retention of physical features. In other words, it keeps its shape even under harsh weather conditions. So if you’ve always wanted a 3D printed replica of Michelangelo’s David as the centrepiece for your garden without having to worry about his ‘special bits’ eroding, ASA has your back.

As the two plastics have similar strength and toughness properties, they also both respond well to finishing, such as acetone smoothing. You can smooth ASA prints in acetone vapor similar to how you would with ABS. 

While we’re discovering the benefits of ASA, it would be worthwhile to consider the plastic’s density. Whereas ABS has a density of ‘1.04’ per g/cm3, ASA has a substantial density of ‘1.07’ per g/cm3.

But what does that mean?

Well, simply put, a plastic with a density of less than 1 per g/cm3 will float on water. So how does this carry over into our ABS vs ASA debate? They’re virtually the same in this department, although ASA has a slightly higher density than ABS.

So, now that we have all those specifics written down and explained in a collection of neat paragraphs, it would be a little easier on the eye to compare them face to face.

DIFFERENCES:

 

ABS

ASA

Best Printing Temperature

240-260°C / 464-500°F

240-250°C / 464-482°F

Heated Bed Temperature

110°C / 230°F

110-115°C / 230-239°F

Fan Power

45%

10%

Density

1.04 per g/cm3

1.07 per g/cm3

Yellowing Over Time (When Exposed to UV)

Moderate

Low

UV Resistance

Moderate

High

Weather Resistance

Moderate

High

 

All right, so what we’re seeing here are quite a few similarities between ABS and ASA filament; they have comparable temperatures for printing; both on the printer’s hotend and heated bed, as well as a marginal difference in density.

So that’s good to know; ASA filament is of a strong build like ABS and, in addition, should be very easy to print for those already familiar with ABS.

Let’s look at the few key differences to help you decide which of the two you should be buying.

First off; cooling. This is one of the most important differences to remember during printing. When printing with ASA, the printer’s cooling fan should be turned down to approximately 10% power.

The reason for this is simple: cool it too fast, and the ASA is susceptible to cracking. And, let’s be honest, you don’t want your statue of David losing his masculinity, like he had once the pope was through with him.

So, easy reminder for printing with ASA: turn your fans low, to about 10% power and make sure your printing environment isn’t drafty, or cold. ASA can be cold after the printing process of course, it’s just while the material is cooling – this process needs to be slow.

The final big difference between ABS and ASA is UV/weather resistance.

You’ll have noticed quite a bit of mention in this article about ASA filament’s excellent ability to retain it’s shape and colour even in rough weather. This, more than anything, would be the deciding factor if you wanted to make the change from ABS to ASA.

If you are printing indoor items, then ABS is as good as ASA in terms of life and colour/shape-retention. However, if you want that magnificent statue of David to last for years in your front yard, in all his naked glory, ASA is the way to go. It will last longer than ABS in the sun and doesn’t yellow, at least not noticeably, under UV radiation.

Now, the decision is yours to make; ABS or ASA. And it shouldn’t be a hard one, as we’ve already discussed that the biggest influencing factor should be what you are printing and where you want to put; inside or outside the house.

If you are thinking of buying ASA filament, it is worth bearing in mind that it is slightly more expensive than ABS, but that makes sense due to it’s sturdier outdoor design and purpose.

We advise you to buy from somewhere that offers excellent support along with excellent high quality filament. Ahem… If you were looking for either of these materials, you can view our selection of ABS here and ASA here

 

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